The abuse of pharmaceutical medicaments such as opioids has now become a high profile topic. This abuse often takes the form of extracting, injecting, chewing or snorting different prescription drugs, in contrast to their normal prescribed administration route, in order to increase the effect of the drugs.
A further problem associated with pharmaceutical medicaments is that they can be employed in spiking of drinks in other words so-caged “drug rape” and “drug robbery”, etc. Incidents where fast dissolving tablets or powders containing hypnotic type compounds are secretly added to drinks in pubs and clubs have been reported.
It is imperative that manufacturers consider and seriously address the issue of misuse of dosage units.
Some of the most widely used current pharmaceutical medicaments are tablets, powder filled capsules and filled soft gel capsules.
Tablets are a popular way of administering drugs but are open to abuse as they are crushable and the active ingredient can therefore be easily absorbed, extracted, dissolved, ingested or snorted.
Some dosage units are formulated so that they maintain a sustained release profile. Such medicaments contain extremely high doses of active pharmaceutical agent that are released slowly over a long period of time. However, in tablet form this type of dosage unit can be abused by chewing and mixing with saliva, or by crushing, which destroys the sustained release matrix and releases a large dose of the active pharmaceutical agent in a short space of time.
Another popular way of administering pharmaceutical medicaments, which is similar to using tablets, is to use capsules filled with powder. Powder filled capsules can incorporate small amounts of high melting point materials or waxes, but not to any great extent. This is principally due to the method that these capsules are manufactured. In particular, the powder needs to be able to flow such that it can be dispensed by machines when manufacturing the powder filled capsules. Therefore, the powder cannot be made too waxy, gel-like or sticky as it will not flow through the machinery and will not be able to be dispensed properly.
A further method employed for administering pharmaceutical medicaments is to use soft gel capsules that can be manufactured by injecting materials between sheets of wet gelatin. At present, soft gel capsule manufacturing is limited to processing at temperatures of <40° C. and therefore are unsuitable for encasing liquefied high melting point materials. Moreover, the contents of soft gel capsules re-liquefy when heated to 40° C. (which is very close to body temperature) and therefore are easy to extract and inject, making them open to abuse. All types of dosage unit are potentially subject to abuse. However, self-abusers tend to abuse sustained release formulations as these are designed to release drug substances over a prolonged period and thus have a much higher drug loading than dosage units designed for immediate release. Sustained (or prolonged) release formats (normally tablets) do have some inbuilt abuse resistance (as they are specifically designed to release drug substance slowly) but this is overcome immediately by powdering the dosage unit when the drug content can be extracted or absorbed extremely quickly due to the large surface area of the powdered material.
Therefore it would be desirable to mitigate at least some of the problems associated with the prior art. Accordingly, it is an object of the present invention to provide improved abuse resistant formulations and capsules containing such.